When one half teaspoon of baking soda is dissolved in your stomach, what volume of carbon dioxide gas would be produced at body temperature and 1.00 atm. pressure? On the average, one half teaspoon of baking soda contains 2.40 g of sodium bicarbonate. Assume the net ionic reaction, H+ + HCO3- ==> H2O(l) + CO2(g), goes to completion at these stomach conditions.

We assume there is enough acid in the stomach to react with all of the NaHCO3; i.e., NaHCO3 is the limiting reagent.

mols NaHCO3 = grams/molar mass = ?
1 mol NaHCO3 produces 1 mol CO2 according to your equation; therefore, mols NaHCO3 - mols CO2 produced.
Then use PV = nRT. YOu know P, solve for V, n = from above, R and T you know. Remember to use T in kelvin. V will be in liters.

So will the mol value for PV=nRT be 0?

No, and your gut feeling should tell you that is not right for a zero for n makes V = 0 and you know that can't be right

Look at my post. You calculate mols NaHCO3 from the mass at the begining and mols CO2 then = mols NaHCO3. That is n.

Because mol NaHCO3=mol CO2 produced

If not, how can I find mol CO2

Okay thank you, I understand now

Yes, the equation tells you that 1 mol NaHCO3 produces 1 mol CO2; therefore, mols NaHCO3 = mols CO2.